The present invention relates to a format adjustment device for adjusting the format of at least one functional element on a packaging machine.
In packaging technology products are often packed in cardboard containers. To this end, flat cardboard blanks are removed from a stack, supplied to a forming and folding apparatus and pressed by a forming tool by means of plungers and consequently they are formed into a cardboard container. The formed cartons are then supplied to a packaging system, filled and re-closed.
In order to be able to produce several different carton formats on the same machine, individual parts of the machine have to be adapted or adjusted to said different sizes. For example, the following modules of the machine have to be converted to the various carton formats: cardboard blank magazine, cardboard blank outlet, plungers, forming tool, positions of the glue nozzles in the case of hot glue variants, various blank supplying means and carton removal conveyors.
Known solutions realize the adjustment in different ways.
For example, it is known to exchange format-dependent parts such as the plunger and the forming tool. Said so-called interchangeable tools are adapted to the corresponding carton format. The advantage of said solution is that the tools are pre-adjusted and consequently a short ramp-up (start time) is achieved for the production; this means the machine is up and running again correctly with the new format and at maximum efficiency within a short time. No adjusting has to be done at the start of production.
A disadvantage is that above all in the case of many formats many replacement tools are needed, which is expensive and requires a lot of storage space. The replacement tools are often very heavy such that lifting tools have to be used sometimes for installation and removal.
It is also known that in the case of tools, e.g. forming tools, the lateral walls and corner elements are mounted on rails and are adjustable with spindles. The spindles can be operated by hand as well as by setting motors. Such adjustments are also made for lateral guides or for the carton magazine.
An advantage is that no expensive conversion work has to be carried out during a format change. The ramp-up time in the case of the variant with the setting motor is very short as the presetting, as a rule, is able to be stored. A disadvantage in the case of the motor-driven variant, however, is that it is very expensive as separate setting motors with actuating means have to be used for each dimension. The error susceptibility is also higher as more (electric) components are in use. The manually adjustable variant is certainly somewhat more cost-efficient but is more difficult to adjust. In this case, the adjustment has to be performed using graduations mounted on the adjustment element. In addition, the fine adjustment has to be made every time at the start of production, that is the ramp-up time becomes longer, which leads to impaired availability. In the case of multi-track variants, said adjustment has to be made on each track; there are therefore numerous spindles to adjust, which is cost-intensive and leads to a high degree of error susceptibility.
A further variant is the fastening of the individual elements of the forming tool to the rails by means of clamping screws. This is certainly also a cost-efficient variant, but has similar disadvantages of adjusting the spindle by hand.